3D pen



FIG. 1 is a perspective view of a 3D pen showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the drawings are included for the purpose of showing portions of the 3D pen that form no part of the claimed design. 

CLAIM The ornamental design for a 3D pen, as shown and described. 